1. Field of the Invention
The present invention relates to a dielectric waveguide line for transmitting a high-frequency signal of the microwave band or the millimeter band, and particularly to a dielectric waveguide line having a bent or branched portion.
2. Description of the Related Art
In a high-frequency circuit which handles a high-frequency signal of the microwave band or the millimeter band, a transmission line for transmitting the high-frequency signal is requested to have a reduced size and a small transmission loss. If such a transmission line can be formed on or in a substrate which constitutes a circuit, it is advantageous to miniaturization. In the prior art, therefor, a strip line, a microstrip line, a coplanar line, or a dielectric waveguide line is used as such a transmission line.
Among these lines, a strip line, a microstrip line, and a coplanar line have a structure which consists of a dielectric substrate, a signal line composed of a conductor layer, and a ground conductor layer, and in which an electromagnetic wave of a high-frequency signal propagates through the space and the dielectric around the signal line and the ground conductor layer. These lines have no problem in transmitting signals within a band of not more than 30 GHz. For transmission of signals of 30 GHz or more, however, a transmission loss is easily produced.
By contrast, a waveguide line is advantageous because the transmission loss is small also in the millimeter band of not less than 30 GHz. In order to utilize excellent transmission characteristics of such a waveguide, also a line which can be formed in a multilayer substrate has been proposed.
In Japanese Unexamined Patent Publication JP-A 6-53711 (1994), for example, a waveguide line is proposed in which a dielectric substrate is sandwiched between a pair of conductor layers and side walls are formed by two rows of via holes through which the conduct layers are connected to each other. In the waveguide line, the four sides of a dielectric material are surrounded by pseudo conductor walls configured by the conductor layers and the via holes, whereby the region in the conductor walls is formed as a line for signal transmission. The waveguide line has a very simple structure and an apparatus can be miniaturized as a whole.
When a high-frequency circuit is to be configured, usually, formation of a bent or branched portion in a wiring circuit of a transmission line is inevitable. Particularly, in the case where a feeder line for array antennas or the like is to be formed, a branch must be formed in a wiring circuit of a transmission line.
However, a strip line, a microstrip line, and a coplanar line have a problem in that, because a signal line is not completely covered with a ground conductor layer, formation of a branch at a midpoint of a transmission line causes an electromagnetic wave to be radiated from the branch, thereby increasing the transmission loss.
As a dielectric waveguide line, furthermore, known is an NRD guide having a structure in which a dielectric line is sandwiched between two ground conductor plate and the portion between the ground conductor plates and other than the dielectric waveguide line is filled with the air. In order to form a branch in the structure, a method in which two bent lines are coupled together to form a directional coupler is employed. When a bent portion exists in a line, however, there arises another problem in that different propagation modes are produced depending on the shape and the transmission loss is increased and hence strict restriction is imposed on the design. A dielectric waveguide line is usually made of fluororesin or the like. Particularly, a line which is to be used in a high frequency region has a reduced size and hence it is difficult to work a bent position and the like, thereby causing a further problem in that it is difficult to obtain such a line by mass production. Moreover, there is a further problem in that it is difficult to form such a line as a wiring of a high frequency circuit on or in a dielectric substance.
A conventional waveguide has a structure in which an electromagnetic wave propagates through a space surrounded by metal walls, and hence does not produce a loss due to a dielectric. Therefore, the loss at a high frequency is small, and, even when there is a branch, a radiation loss is not produced. However, such a waveguide has a problem in that the size of the waveguide is larger than that of a transmission line using a dielectric. By contrast, a dielectric waveguide line which is filled with a dielectric of a specific dielectric constant of xcex5r can be produced at a size which is 1/{square root over ( )}xcex5r of that of a conventional one. However, such a waveguide also has a problem in that it is difficult to form such a waveguide on or in a dielectric substrate.
In a dielectric waveguide line such as that proposed in Japanese Unexamined Patent Publication JP-A 6-53711 (1994), when a bent or branched portion is simply formed in a line for signal transmission which is surrounded by pseudo conductor walls configured by the pair of conductor layers and the two rows of via holes, the electromagnetic field is disturbed, thereby producing a problem in that the transmission loss is increased.
In order to produce a wiring circuit of a transmission line in which a branch for forming a feeder line for an array antenna or the like in a dielectric substrate, therefore, it has been requested to develop a branch structure of a dielectric waveguide line which can be formed in a dielectric substrate, which does not radiate an electromagnetic wave, and in which the transmission loss is small.
The invention has been conducted in view of the above-discussed circumstances. It is an object of the invention to provide bent and branched portions of a dielectric waveguide line which can be formed in a dielectric substrate, in which a high-frequency signal does not radiate or leak an electromagnetic wave, and which has excellent transmission characteristics of a small transmission loss.
The inventors have intensively studies the above-discussed problems. As a result, the inventors have found that, when, in a dielectric waveguide line and in a bent portion disposed in a transmission line having a structure which is formed by complete covering of a pair of conductor layers that are electrically connected to two rows of through conductor groups disposed in a dielectric substrate, the two rows of through conductor groups have a predetermined arrangement structure, radiation and leakage of an electromagnetic wave of a high-frequency signal hardly occur and excellent transmission characteristics of a low transmission loss can be realized even when such a bent portion exists in the transmission line.
Moreover, it has been found that, when, in a dielectric waveguide line, a transmission line comprising a dielectric waveguide line having a structure formed by completely covering upper and lower portions of two rows of through conductor groups with a pair of conductor layers which are electrically connected to the two rows of through conductor groups is disposed in a dielectric substrate, and through conductors of the two rows of through conductor groups have a predetermined arrangement structure in a branch in which the transmission line is connected in a T-like shape and transmission directions of a high-frequency signal are perpendicular to each other, a branch structure of a transmission line in which radiation and leakage of an electromagnetic wave of a high-frequency signal hardly occur and which has excellent transmission characteristics of a low transmission loss can be realized. Moreover, it has been found that, in a branch where second and third transmission lines which are disposed in parallel with a first dielectric waveguide line are connected together so that transmission directions of a high-frequency signal are parallel to each other, through conductors of through conductor groups have a predetermined arrangement structure, a branch structure of a transmission line in which radiation and leakage of an electromagnetic wave of a high-frequency signal hardly occur and the power ratio after branch can be arbitrarily set, and which has excellent transmission characteristics of a low transmission loss can be realized. Furthermore, it has been found that, in a branch where fourth to sixth transmission lines which are disposed in parallel with second and third transmission lines are connected together so that transmission directions of a high-frequency signal are parallel to each other, through conductors of two rows of through conductor groups have a predetermined arrangement structure, a branch structure of a transmission line in which radiation and leakage of an electromagnetic wave of a high-frequency signal hardly occur and the power ratio after branch can be arbitrarily set, and which excellent transmission characteristics of a low transmission loss can be realized.
In a first aspect of the invention, there is provided a dielectric waveguide line having a bent portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched: and two rows of through conductor groups which are formed to electrically connect the conductor layer to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, the high-frequency signal being transmitted through a region surrounded by the conductor layers and the through conductor groups, wherein the two rows of through conductor groups are arranged to form bent portions, the bent portion of one of the two rows being formed into an edgy shape a bending point of which is one of the through conductors, the bent portion of the other of the two rows being formed into an arcuate shape a center of which is the one through conductor, having a radius equal to the constant width (d).
In a second aspect of the invention, there is provided a dielectric waveguide line having a bent portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, the high-frequency signal being transmitted through a region surrounded by the conductor layers and the through conductor groups, wherein the two rows of through conductor groups are arranged to form bent portions, the bent portion of one of the two rows being formed into an edgy shape a bending point of which is one of the through conductors, the bent portion of the other of the two rows being formed into an edgy shape corresponding to a base of an isosceles triangle a vertex of which is the bent point of the one row, having a height equal to the constant width (d).
In a third aspect of the invention, there is provided a dielectric waveguide line having a bent portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, the high-frequency signal being transmitted through a region surrounded by the conductor layers and the through conductor groups, wherein the two rows of through conductor groups are arranged to form bent portions, the bent portions being arranged in a concentric arcuate shape.
The dielectric waveguide line according to the invention comprises: the pair of conductor layers between which the dielectric substrate is sandwiched; and the two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of the signal wavelength of the high-frequency signal in the transmission direction of the high-frequency signal, and at the constant width (d) in a direction perpendicular to the transmission direction. Therefore, the conductor layers and the through conductor groups form portions corresponding to pseudo conductor walls of a dielectric waveguide which are parallel to the E and H planes or the H and E planes, respectively. Consequently, a transmission line for a high-frequency signal and having characteristics similar to those of a dielectric waveguide can be obtained by a flat plate structure using a dielectric substrate.
In the dielectric waveguide line of the invention, since the two rows of through conductor groups are arranged in the above-mentioned specific structure, radiation of electromagnetic wave hardly occurs and excellent transmission characteristics of low transmission loss can be realized.
In a fourth aspect of the of the invention, there is provided a branch structure of a dielectric waveguide line having a T-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first and second dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and the through conductor groups being disposed, a tip end of the first dielectric waveguide line being connected to an opening disposed in one side of the second dielectric waveguide line so that transmission directions of the lines are perpendicular to each other, wherein a width (w) of the opening satisfies relationships of d less than wxe2x89xa65d with respect to the constant width (d), and the tip end of the first dielectric waveguide line is connected to the opening by connection through conductor groups linearly arranged.
In a fifth aspect of the invention there is provided a branch structure of a dielectric waveguide line having a T-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first and second dielectric waveguide lines which transmit the high-frequency signal thorough a region surrounded by the conductor layers and the through conductor groups being disposed, a tip end of the first dielectric waveguide line being connected to an opening disposed in one side of the second dielectric waveguide line so that transmission directions of the lines are perpendicular to each other, wherein a width (w) of the opening satisfies relationships of d less than wxe2x89xa65d with respect to the constant width (d), and the tip end of the first dielectric waveguide line is connected to the opening by connection through conductor groups arcuately arranged.
In a sixth aspect of the invention, there is provided a branch structure of a dielectric waveguide line having a T-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first and second dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and the through conductor groups being disposed, a tip end of the first dielectric waveguide line being connected to an opening disposed in one side of the second dielectric waveguide line so that transmission directions of the lines are perpendicular to each other, wherein a width (w) of the opening satisfies relationships of d less than wxe2x89xa65d with respect to the constant width (d), and the tip end of the first dielectric waveguide line is connected to the opening by intermediate through conductor groups which have a width equal to the width of the opening and a length that is about one quarter of a guide wavelength of the high-frequency signal.
In a seventh aspect of the invention, there is provided a branch structure of a dielectric waveguide line having a T-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of the signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first and second dielectric waveguide lines which transmit the high-frequency signals through a region surrounded by the conductor layers and the through conductor groups being disposed, a tip end of the first dielectric waveguide line being perpendicularly connected to an opening disposed in one side of the second dielectric waveguide line, wherein the through conductor groups in another side opposed to the opening of the second dielectric waveguide line are formed along two arcs which are respectively centered at through conductors at ends of the opening and which have a radius equal to the constant width (d), to have a vertex at an intersection of the two arcs.
In an eighth aspect of the invention, there is provided a branch structure of a dielectric waveguide line having T-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first and second dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and the through conductor groups being disposed, a tip end of the first dielectric waveguide line being perpendicularly connected to an opening disposed in one side of the second dielectric waveguide line, wherein the through conductor groups in another side opposed to the opening of the second dielectric waveguide line are formed along oblique sides of a triangle which has a base equal to the width of the opening, a vertex on a center line of the first dielectric waveguide line, and a height of d/2 or less.
In a ninth aspect of the invention, in the branch structure of the dielectric waveguide line having a T-branched portion of any one of the fourth through sixth aspects, the through conductor groups in another side opposed to the opening of the second dielectric waveguide line are formed along two arcs which are respectively centered at through conductors at ends of the opening and which have a radius equal to the constant width (d), to have a vertex at an intersection of the two arcs.
In a tenth aspect of the invention, in the branch structure of a dielectric waveguide line having a T-branched portion of any one of the fourth through sixth aspects, the through conductor groups in another side opposed to the opening of the second dielectric waveguide line are formed along oblique sides of a triangle which has a base equal to the width of the opening, a vertex on a center line of the first dielectric waveguide line, and a height of d/2 or less.
In an eleventh aspect of the invention, there is a branch structure of a dielectric waveguide line having a T-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first and second dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and the through conductor groups being disposed, a tip end of the first dielectric waveguide line being connected to an opening disposed in one side of the second dielectric waveguide line with setting transmission directions of the lines to be perpendicular to each other, wherein a width (w) of the opening satisfies relationships of d less than wxe2x89xa62d with respect to the constant width (d), the tip end of the first dielectric waveguide line is connected to the opening by connection through conductor groups in which through conductors are arranged along arcs, and the through conductor groups in another side opposed to the opening of the second dielectric waveguide line is formed along two arcs which are respectively concentric with the arcs and which have a radius equal to a sum (r+d) of a radius (r) of the arcs and the constant width (d), to have a vertex at an intersection of the two arcs.
According to the branch structure of a dielectric waveguide line having a T-branched portion of the invention, the pair of conductor layers and the two rows of through conductor groups constituting the dielectric waveguide line disposed in the dielectric substrate form portions corresponding to pseudo conductor walls of a dielectric waveguide which are parallel to the E and H planes or the H and E planes, respectively, and a transmission line for a high-frequency signal and having characteristics similar to those of a dielectric waveguide can be obtained by a flat plate structure using a dielectric substrate. In such wiring of transmission lines, when a branch having a structure in which two transmission lines are connected to each other perpendicularly or in a T-like shape is to be formed, and two rows of through conductor groups are arranged in the above-mentioned specific structure, thereby obtaining a structure in which radiation of an electromagnetic wave hardly occurs in the branch and excellent transmission characteristics of a low transmission loss can be realized.
In a twelfth aspect of the invention, there is provided a branch structure of a dielectric waveguide line having a parallel-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first to third dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and the through conductor groups are disposed while the second and third dielectric waveguide lines share one of the rows of through conductor groups, and a tip end of the first dielectric waveguide line is connected to ends of tip ends of the second and third dielectric waveguide lines by connection through conductor groups while the tip ends of the second and third dielectric waveguide lines are opposed to the tip end of the first dielectric waveguide line so that transmission directions of the high-frequency signal in the dielectric waveguide lines are parallel to each other.
According to the configuration of the invention, while the width (d) of the first dielectric waveguide line in front of the branch is widened through the connection through conductor groups, the first dielectric waveguide line is connected to the second and third dielectric waveguide lines so that transmission directions of a high-frequency signal are parallel to each other, and the high-frequency signal is branched from the first dielectric waveguide line into the second and third dielectric waveguide lines, thereby changing the width (d) of the dielectric waveguide line to the width (2d) of a connection dielectric waveguide line. Therefore, mismatching of the characteristic impedance in the branched portion can be made smaller than that in the case of a T-branch in which the width is usually changed to the width a (2d less than  less than a less than ∞) of a connection dielectric waveguide line. The reflection of a high-frequency signal in the branched portion can be reduced, and the transmission loss can be reduced.
In a thirteenth aspect of the invention, there is provided a branch structure of a dielectric waveguide line having a parallel-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first to third dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and through conductor groups are disposed in parallel while the second and third dielectric waveguide lines are arranged with aligning tip ends so that a distance (A) between outer through conductor groups satisfies relationships of 2d less than Axe2x89xa63d with respect to the constant width (d), tip ends of adjacent rows of through conductor groups are connected to each other by auxiliary connection through conductor groups, and a tip end of the first dielectric waveguide line is connected to ends of the tip ends of the second and third dielectric waveguide lines by connection through conductor groups while the tip ends of the second and third dielectric waveguide lines are opposed to the tip end of the first dielectric waveguide lines so that transmission directions of the high-frequency signal in the dielectric waveguide lines are parallel to each other.
According to the configuration of the invention, while the width (d) of the first dielectric waveguide line in front of the branch is widened to the width A (2d less than Axe2x89xa63d) through the connection through conductor groups, the second and third dielectric waveguide lines are connected with forming a distance of (A-2d) therebetween and in parallel with each other, and a high-frequency signal is branched from the first dielectric waveguide line into the second and third dielectric waveguide lines, thereby changing the width of the dielectric waveguide line from the width (d) of the first dielectric waveguide line to the width (A) of a connection through conductor groups. Therefor, mismatching of the characteristic impedance in the branched portion can be made smaller than that in the case of a usual T-branch. The distance (A-2d) can be formed between the second and third dielectric waveguide lines. The freedoms in design are enhanced and the isolation property can be improved.
In a fourteenth aspect of the invention, in the branch structure of a dielectric waveguide line having a parallel-branched portion of the abovementioned twelfth or thirteenth aspects of the invention, through conductors for adjusting a power ratio after branch are formed between the two rows of through conductor groups of at least one of the second and third dielectric waveguide lines.
According to the configuration of the invention, the through conductors for adjusting a power ratio are formed in at least one of the second and third dielectric waveguide lines, for example, in the third dielectric waveguide line. Consequently, the characteristic impedance of the third dielectric waveguide line is higher than the characteristic impedances of the first and second dielectric waveguide lines, and the cut-off frequency of the third dielectric waveguide line becomes higher. With respect to an electromagnetic wave which has propagated through the first dielectric waveguide line, therefore, a wave of a frequency between the cut-off frequency of the second dielectric waveguide line and that of the third dielectric waveguide line propagates through only the second dielectric waveguide line, and a wave of a frequency which is not lower than the cut-off frequency of the third dielectric waveguide line propagated through both the second and third dielectric waveguide lines. Namely, as the frequency is higher, an electromagnetic wave propagates more easily through the third dielectric waveguide line. As a result, the power ratio after branch is not 1:1 or the evenly distributed branch is not performed. Therefore, an arbitrary power ratio can be obtained by adequately selecting the position and number of the through conductors for adjusting a power ratio.
In a fifteenth aspect of the invention, in the branch structure of a dielectric waveguide line having a parallel-branched portion of the abovementioned twelfth or thirteenth aspects of the invention, a center line of the first dielectric waveguide line is shifted from a center line of the second and third dielectric waveguide lines.
According to the configuration of the invention, the center line of the first dielectric waveguide line is shifted from the center line of the second and third dielectric waveguide lines by a distance (h:0 less than h less than d/2) toward, for example, the second dielectric waveguide line. In this case, propagation to the second dielectric waveguide line is made easier in accordance with the degree of the distance (h). In other words, an arbitrary power ratio can be obtained by adequately selecting the distance (h). When the distance (h) is 0, the power ratio after the branch is 1:1.
Alternatively, the power ratio after branch may be selected while the configurations of the fourteenth and fifteenth aspects are combined together.
In a sixteenth aspect of the invention, there is provided a branch structure of a dielectric waveguide line having a parallel-branched portion comprising: a pair of conductor layers between which a dielectric substrate is sandwiched; and two rows of through conductor groups which are formed to electrically connect the conductor layers to each other at repetition intervals not more than one half of a signal wavelength of a high-frequency signal in a transmission direction of the high-frequency signal, and at a constant width (d) in a direction perpendicular to the transmission direction, first to sixth dielectric waveguide lines which transmit the high-frequency signal through a region surrounded by the conductor layers and the through conductor groups are disposed while the second and third dielectric waveguide lines are juxtaposed with opposing ends of one side of the second and third dielectric waveguide lines to one end of the first dielectric waveguide line so that transmission directions of the high-frequency signal are parallel to each other, and the fourth to sixth dielectric waveguide lines are juxtaposed with opposing ends of one side of the fourth to sixth dielectric waveguide lines to ends of other side of the second and third dielectric waveguide lines, and placing the fourth and sixth dielectric waveguide lines on sides of the fifth dielectric waveguide line so that transmission directions of the high-frequency signal are parallel to each other, the second and third dielectric waveguide lines are disposed in parallel with aligning the tip ends of the one side and the tip ends of the other side so that a distance (A) between outer through conductor groups satisfies relationships of 2dxe2x89xa6Axe2x89xa63d with respect to the constant width (d), tip ends of the one side and tip ends of the other side of adjacent rows of through conductor groups are connected to each other by first and second auxiliary connection through conductor groups, and a tip end of the first dielectric waveguide line is connected to both ends of the tip ends of the one side of the second and third dielectric waveguide lines by first connection through conductor groups, and the fourth to sixth dielectric waveguide lines are disposed in parallel with aligning the tip ends of the one side so that a distance (B) between outer through conductor groups of the fourth and sixth dielectric waveguide lines satisfies relationships of 3dxe2x89xa6Bxe2x89xa64d with respect to the constant width (d), tip ends of adjacent through conductor groups of the fourth and fifth dielectric waveguide lines are connected to each other by third auxiliary connection through conductor groups, tip ends of adjacent through conductor groups of the fifth and sixth dielectric waveguide lines are connected to each other by fourth auxiliary connection through conductor groups, and ends of the other side of the second and third dielectric waveguide lines are connected to both ends of the one side of the fourth to sixth dielectric waveguide lines by second connection through conductor groups.
According to the configuration of the invention, one dielectric waveguide line can be branched into three dielectric waveguide lines. In this case, when the configuration of the twelfth or thirteenth is repeated, the transmission loss in the branched portion can be reduced.
In a seventeenth aspect of the invention, in the branch structure of a dielectric waveguide line having a parallel-branched portion of the abovementioned sixteenth aspects of the invention, through conductors for adjusting a power ratio after branch are formed between the two rows of through conductor groups of at least one of the second and third dielectric waveguide lines, and/or between the two rows of through conductor groups of at least one of the fourth to sixth dielectric waveguide lines.
According to the configuration of the invention, the configuration of the fourteenth aspect is added to the branch structure of a dielectric waveguide line of the sixteenth aspect in which one dielectric waveguide line is branched into three dielectric waveguide lines. According to this configuration, the power ratio after branch can be arbitrarily set. When the configuration of the fifteenth aspect of the invention is further added, the adjustment width of the power ratio after branch can be further widened.